A former key U.S. military leader is under investigation for allegedly leaking classified information about a secret cyberattack on Iranian nuclear facilities.

The U.S. Department of Justice has told retired Marine General James Cartwright, who was vice chairman of the Joint Chiefs of Staff from 2007 to 2011, that he is a target in the investigation, facing allegations that he provided reporters with information about the covert computer virus, Stuxnet. Targets of U.S. criminal investigations have not yet been charged, but often eventually are.

Stuxnet was part of a broader cyber operation called "Olympic Games" that was created under President George W. Bush and continued by President Barack Obama. The New York Times newspaper reported last year that Cartwright ran the operation.

Iran's government said in November 2010 that a computer virus had temporarily disabled Iranian nuclear enrichment efforts.

The investigation of the leak about the Iran cyberattack is one of several current national security leak investigations under the Obama administration.

Congressional leaders called for the criminal probe into who leaked the information about Stuxnet. Mr. Obama has said his administration will not tolerate such leaks and his administration has carried out more investigations about security disclosures than all previous U.S. presidents combined.

Republicans claimed the Stuxnet operation was leaked to increase Mr. Obama's national security credentials while he was running for reelection last year.